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Published byWinfred Booker Modified over 8 years ago
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Data assimilation in C cycle science Strand 2 Team
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Rationale Problem: Current C models show significant disagreements Complication: Mismatch between GCM grid cells (~270 x 270 Km) and flux footprints (~1 x 1 km) Solution: A model-data framework
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Process models -upscaling EO data: -landcover -phenology Flux towers -processes -parameters Geostats -Spatial drivers -Uncertainty Tall tower /aircraft -Check on upscaling -Inversions
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Progress Uncertainty in parameter extrapolation from flux towers (REFLEX) Improved modelling of deciduous systems using EO Assimilating reflectance data into C models Generating spatial errors for drivers Using tall towers to constrain C models
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REgional Flux Estimation eXperiment (REFLEX) To compare the strengths and weaknesses of various MDF/DA techniques To quantify errors and biases introduced when extrapolating fluxes
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REgional Flux Estimation eXperiment (REFLEX) FluxNet data MODIS MDF Full analysis Model parameters DALEC model Training Runs Deciduous forest sites Coniferous forest sites Assimilation Output
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REgional Flux Estimation eXperiment (REFLEX) FluxNet data MODIS MDF Full analysis Model parameters DALEC model Testing site forecasts with limited EO data MDF MODIS Analysis FluxNet data testing Assimilation
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GPP C root C wood C foliage C litter C SOM/CWD RaRa AfAf ArAr AwAw LfLf LrLr LwLw RhRh D C labile A tolab A fromlab DALEC
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A phenology module allows data assimilation at deciduous sites and an improved capacity to assimilate EO data
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Assimilating EO data Last year we showed a capability for assimilating LAI products Now we can assimilate reflectance data And we can cope with snow contamination
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Observation operator - GORT Leaf reflectance - PROSPECT Empirical soil reflectance function
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Observation operator - GORT Shaded crown Illuminated crown Illuminated soil Shaded soil
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Modelled vs. observed reflectance Band 1Band 2
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Canopy foliage results No assimilation Assimilating MODIS (bands 1 and 2)
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GPP results No assimilation Assimilating MODIS (bands 1 and 2)
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NEP results No assimilation Assimilating MODIS (bands 1 and 2)
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Uncertainty in spatial variation in key controls on the C cycle, such as meteorology, can be quantified using geostatistical techniques
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Planetary Boundary Layer model Canopy Flux model Albedo, LE, Sens. heat, Ts, Evaporation, Transpiration NEP Wind speed, Air temp., PAR, Precipitation, VPD, CO 2 conc. Carbon dynamics model Monte Carlo methods provide a powerful means to invert both flux tower and aircraft data to provide estimates of critical C model parameters
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Modelled and measured boundary layer profiles of potential temperature, mixing ratio and CO2 concentration, BOREAS
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Retrieving parameters using tower data
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Plans Manage, process and publish the outputs of REFLEX Demonstrate regional coupled biosphere- atmosphere model (DALEC-NAME) for tall tower and aircraft inversion
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